Ocular optical system, medical viewer, and medical viewer system

ABSTRACT

The purpose is to provide a higher-quality three-dimensional image with a downsized optical system that does not need interpupillary adjustment. An ocular optical system according to the present disclosure includes, on an optical path viewed from an observer side, at least: a first polarization member; a mirror; a second polarization member; and an image display device in this order. A polarized state in the first polarization member and a polarized state in the second polarization member are orthogonal to each other.

FIELD

The present disclosure relates to an ocular optical system, a medicalviewer, and a medical viewer system.

BACKGROUND

Conventionally, a 3D head-mount display (3D-HMD) as disclosed in PatentLiterature 1 has been known as an example of an image display device. Inthe 3D-HMD, two ocular optical systems corresponding to each of a righteye and a left eye are disposed side by side at an interpupillarydistance, and parallax images are displayed on image displays includedin the ocular optical systems. In this manner, an observer wearing the3D-HMD can three-dimensionally observe images displayed on the imagedisplays.

CITATION LIST Patent Literature

Patent Literature 1: WO 2015/125508

SUMMARY Technical Problem

In the above-mentioned 3D-HMD, the interpupillary distance of the rightand left ocular optical systems is required to be adjusted depending onan interpupillary distance of the observer by the observer before use.The interpupillary distance corresponds to a distance between a lookposition of the observer in the right eye ocular optical system and alook position of the observer in the left eye ocular optical system. Thereason why preadjustment is required is that, when adjustment is notperformed, an image appearing on the image display device is vignettedto produce an unobservable region. However, the work of adjusting theinterpupillary distance described above is complicated, and theelimination of interpupillary adjustment is strongly required.

Furthermore, in the above-mentioned HMD configuration, the relativepositions of the eye and the ocular optical system are fixed by thehead-mount system literally. Thus, the above-mentioned HMD configurationcannot be used in the state where the user wears eyeglasses.Accordingly, the focus position of the ocular optical system needs to beadjusted (that is, diopter adjustment) depending on visual power of theobserver.

The interpupillary adjustment and the diopter adjustment are complicatedand required to be eliminated in medical sites where swiftness isrequired.

The distance between the right eye and the left eye of human are greatlydifferent among individuals. In order to enable an image displayed on animage display device to be observed without vignetting even when theocular optical system is used by observers having differentinterpupillary distances, the eye box (range within which virtual imageis visually recognized) of the ocular optical system is required to beenlarged. In other words, in order to prevent vignetting of effectivelight beams even when the position of the eye is eccentric, the parteffective diameter of a lens constituting the ocular optical systemneeds to be set to be large.

Depending on the size of an image display device used for an ocularoptical system, when two ocular optical systems are arranged side byside at an interpupillary distance, an image display device in the righteye ocular optical system and an image display device in the left eyeocular optical system may interfere with each other to cause a problem.In this case, when the image display device used is downsized, theinterference may be avoided. However, in practice, it is difficult toachieve both the enlargement of the eye box described above and thedownsizing of the image display device for the following reasons.

The size of an observation image (virtual image of image appearing onimage display device) is determined by specifications. Thus, when theimage display device is downsized while maintaining the size of theobservation image determined by specifications, the focal length of theocular optical system is required to be shorten (in other words, themagnification of the ocular optical system is required to be enlarged).In this case, in consideration of the setting of a large effectivediameter, the curvature of a lens needs to be decreased in order tosecure the edge thickness of each lens constituting the ocular opticalsystem, and power of each lens decreases. As a result, in order tocompensate for small power of each lens, the number of lenses increases,and the ocular optical system is increased in size and weight.

For the reasons described above, there is a limit in terms of opticaldesign to downsizing of the image display device, and hence it isconceivable to fold the optical path by a mirror. However, when such afolding configuration is employed, a virtual image that is not reflectedby the mirror but directly reaches an observer is formed. Such a virtualimage that is not reflected by the mirror but directly reaches theobserver is called “ghost”. When the ghost is generated, the observersees originally unnecessary ghosts on both right and left sides of athree-dimensional image, which causes a problem of decrease in imagequality.

Thus, in view of the above-mentioned circumstances, the presentdisclosure proposes an ocular optical system capable of providing ahigher quality image with a downsized optical system that does not needinterpupillary adjustment, and a medical viewer and a medical viewersystem including the ocular optical system.

Solution to Problem

According to the present disclosure, an ocular optical system isprovided that includes, on an optical path viewed from an observer side,at least: a first polarization member; a mirror; a second polarizationmember; and an image display device in this order, wherein a polarizedstate in the first polarization member and a polarized state in thesecond polarization member are orthogonal to each other.

Moreover, according to the present disclosure, a medical viewer,comprising an ocular optical system is provided that includes, on anoptical path viewed from an observer side, at least: a firstpolarization member; a mirror; a second polarization member; and animage display device in this order, wherein a polarized state in thefirst polarization member and a polarized state in the secondpolarization member are orthogonal to each other.

Moreover, according to the present disclosure, a medical viewer systemis provided that includes: an image processing unit for performing imageprocessing on an image in which a surgical site that is a site subjectedto surgery is taken, and outputting an obtained surgical site takenimage; and a medical viewer for presenting the surgical site taken imageoutput from the image processing unit to an observer, wherein themedical viewer includes an ocular optical system including, on anoptical path viewed from an observer side, at least: a firstpolarization member; a mirror; a second polarization member; and animage display device in this order, and a polarized state in the firstpolarization member and a polarized state in the second polarizationmember are orthogonal to each other.

According to the present disclosure, light beams forming an image to bedisplayed on the image display device become a predetermined polarizedstate by the second polarization member, and are reflected by thereflection surface of the mirror to reach the first polarization member.The polarized state in the first polarization member and the polarizedstate in the second polarization member are orthogonal to each other,and hence light beams that have reached the first polarization memberthrough the above-mentioned path are transmitted through the firstpolarization member to reach an observer, and light beams that havereached the first polarization member without being reflected by themirror cannot be transmitted through the first polarization member.

Advantageous Effects of Invention

As described above, according to the present disclosure, ahigher-quality image can be provided with a downsized optical systemthat does not need interpupillary adjustment.

The above-mentioned effect is not necessarily limited, and any effectdescribed herein or other effects that could be understood from thespecification may be exhibited together with or in place of theabove-mentioned effect.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is an explanatory diagram schematically illustrating an ocularoptical system according to an embodiment of the present disclosure.

FIG. 1B is an explanatory diagram schematically illustrating the ocularoptical system according to the embodiment.

FIG. 2 is an explanatory diagram schematically illustrating the ocularoptical system according to the embodiment.

FIG. 3A is an explanatory diagram schematically illustrating the ocularoptical system according to the embodiment.

FIG. 3B is an explanatory diagram schematically illustrating the ocularoptical system according to the embodiment.

FIG. 4 is an explanatory diagram schematically illustrating an exampleof the ocular optical system according to the embodiment.

FIG. 5 is an explanatory diagram for describing an ocular lens in theocular optical system according to the embodiment.

FIG. 6 is an explanatory diagram for describing the ocular lens in theocular optical system according to the embodiment.

FIG. 7 is an explanatory diagram for describing the ocular lens in theocular optical system according to the embodiment.

FIG. 8 is an explanatory diagram for describing a medical viewer, amedical viewer system, and a surgical system including the ocularoptical system according to the embodiment.

FIG. 9 is an explanatory diagram for describing an ocular optical systemin a first example.

FIG. 10 is a graph for describing the ocular optical system in the firstexample.

FIG. 11 is a graph for describing an ocular optical system in a secondexample.

FIG. 12 is a graph for describing an ocular optical system in a thirdexample.

FIG. 13 is an explanatory diagram for describing an ocular opticalsystem in a fourth example.

FIG. 14 is a graph for describing the ocular optical system in thefourth example.

DESCRIPTION OF EMBODIMENTS

Referring to the accompanying drawings, preferred embodiments of thepresent disclosure are described in detail below. In the specificationand the drawings, components having substantially the same functionalconfigurations are denoted by the same reference symbols to omitoverlapping descriptions.

The descriptions are given in the following order:

1. Embodiments

1.1 Ocular optical system

1.2 Medical viewer, medical viewer system, and surgical system

2. Examples EMBODIMENTS <Ocular Optical System>

First, an ocular optical system according to a first embodiment of thepresent disclosure is described in detail with reference to FIG. 1A toFIG. 7.

FIG. 1A to FIG. 3B are explanatory diagrams schematically illustratingthe ocular optical system according to the present embodiment. FIG. 4 isan explanatory diagram schematically illustrating an example of theocular optical system according to the present embodiment. FIG. 5 toFIG. 7 are explanatory diagrams for describing an ocular lens in theocular optical system according to the present embodiment.

The ocular optical system according to the present embodiment an opticalsystem for causing an image displayed on an image display device toreach an eye of an observer when the observer looks into the ocularoptical system. In an ocular optical system 10, as schematicallyillustrated in FIG. 1A, at least a first polarization member 101, amirror 103, a second polarization member 105, and an image displaydevice 107 are disposed in this order on an optical path viewed from theobserver side. As illustrated in FIG. 1A, in the ocular optical system10 according to the present embodiment, the optical path is bent by themirror 103, and hence an optical design capable of enlarging the eye boxand downsizing the image display device 107 while eliminating the needof interpupillary adjustment can be achieved. The ocular optical system10 according to the present embodiment can be implemented withoutemploying what is called head-mount system, and hence even when anobserver wears eyeglasses, the observer can observe an image output tothe image display device 107 without diopter adjustment.

FIG. 1A illustrates the monocular ocular optical system 10, but asillustrated in FIG. 1B, two ocular optical systems 10 illustrated inFIG. 1A may be used such that one of the ocular optical systems 10 is anocular optical system 10L for a left eye and the other is an ocularoptical system 10R for a right eye. When the pair of right and leftocular optical systems 10L and 10R as illustrated in FIG. 1B areprovided and parallax images are displayed from the image displaydevices 107 provided in the ocular optical systems 10L and 10R, theobserver can observe a three-dimensional image. In the followingdescription, the two ocular optical systems 10L and 10R are sometimescollectively referred to as “ocular optical systems 10”.

In the ocular optical system 10 according to the present embodiment asillustrated in FIG. 1A and FIG. 1B, a polarized state in the firstpolarization member 101 and a polarized state in the second polarizationmember 105 are orthogonal to each other. Light beams to form an imagedisplayed on the image display device 107 become a predeterminedpolarized state by the second polarization member 105, and are reflectedby a reflection surface of the mirror 103 and then reach the firstpolarization member 101. On the reflection surface of the mirror 103,the polarized state of the light beams changes, due to the reflection,from a polarized state given by the second polarization member 105 to apolarized state orthogonal to the polarized state. As described above,the polarized state in the first polarization member 101 and thepolarized state in the second polarization member 105 are orthogonal toeach other, and hence light beams that have reached the firstpolarization member 101 through the above-mentioned path are transmittedthrough the first polarization member 101 to reach the observer withoutattenuating the light amount.

On the other hand, light beams that have reached the first polarizationmember 101 without being reflected by the mirror 103 (for example,direct image ghost g schematically illustrated in FIG. 2) cannot betransmitted through the first polarization member 101 because thepolarized state thereof is still the polarized state given by the secondpolarization member 105. In this manner, the direct image ghost g thathas reached the first polarization member 101 without being reflected bythe mirror 103 does not reach the observer, and hence the light amountof the direct image ghost g can be attenuated to increase the quality ofimages provided to the observer.

As described above, by using two polarization members whose polarizedstates are orthogonal to each other in combination, an effect thateffective light beams reliably reach an observer while preventing directimage ghosts from reaching the observer can be exerted.

When an optical path folding structure such as the ocular optical systemaccording to the present embodiment is employed, light beams of thedirect image ghost g (hereinafter sometimes referred to as “ghost lightbeams”) pass near the lens effective diameter. Thus, when the lenseffective diameter is increased to downsize the image display device 107and the need of interpupillary adjustment is eliminated, there is atradeoff that the ghost light beams easily reach an observer. However,by using two polarization members 101 and 105 whose polarized states areorthogonal to each other in combination as described above, the directimage ghost can be effectively blocked.

In the ocular optical system 10 according to the present embodiment, thefirst polarization member 101 and the second polarization member 105 arenot particularly limited, and a combination of any publicly knownpolarization members can be used.

For example, the first polarization member 101 and the secondpolarization member 105 may be linear polarizing plates. The firstpolarization member 101 and the second polarization member 105 may becircular polarizing plates each formed from a linear polarizing plateand a ¼ wavelength plate (λ/4 plate).

When the first polarization member 101 and the second polarizationmember 105 are linear polarizing plates, the linear polarizing platesonly need to be installed such that the direction of polarization axis(polarization direction) of one linear polarizing plate is, for example,−45° and the polarization direction of the other linear polarizing plateis, for example, +45°. In this manner, the polarized states orthogonalto each other can be easily created. When the first polarization member101 and the second polarization member 105 are circular polarizingplates, the cost increases as compared with the case where a linearpolarizing plate is used, but the adjustment of a combination ofpolarization directions as in a linear polarizing plate becomesunnecessary, and hence the alignment (adjustment and assembly) of theocular optical system is facilitated.

The combination of the first polarization member 101 and the secondpolarization member 105 is not limited to the above-mentioned examples.For example, the first polarization member 101 may be a linearpolarizing plate, and the second polarization member 105 may be a ½wavelength plate (λ/2 plate). The reason is that the image displaydevice 107 (for example, liquid crystal display (LCD)) generally emitslinearly polarized light by itself, and hence the second polarizationmember 105 is not required to be a linear polarizing plate and a desiredpolarization direction can be obtained by using a 2 plate. When thisconcept is pushed forward, the second polarization member 105 itself canbe eliminated by setting the polarization directions of emission lightof LCDs to ±45 degrees. The first polarization member 101 may be alinear polarizing plate, and the second polarization member 105 may be apolarization member in which a linear polarizing plate and a ½wavelength plate are disposed in this order from the observer side.

In the case of installing the first polarization member 101 and thesecond polarization member 105 as described above, the polarizationmembers may be installed while being bonded to protective glass of animage display device (such as LCD). By installing the first polarizationmember 101 and the second polarization member 105 in this manner, thepossibility of condensation of the polarization member caused bytemperature difference between heat generated from the image displaydevice 107 and low-temperature air ahead can be suppressed to furtherincrease the quality of images provided to the observer. However, whenthe polarization member is simply bonded to protective glass, dustadhering to the surface of the polarization member is easily recognized.Thus, when bonding the polarization member to protective glass, it ispreferred to pay attention to the presence of attachment on the surfacesof the polarization member and the protective glass.

It is preferred that the sizes of the first polarization member 101 andthe second polarization member 105 be set depending on the size of theimage display device 107.

The mirror 103 is a member for reflecting light beams that have beenemitted from the image display device 107 and become a predeterminedpolarized state by the second polarization member 105 by a reflectionsurface thereof to guide the light beams toward the first polarizationmember 101. When the light beams are reflected by the reflection surfaceof the mirror 103, the polarized state of the light beams changes to astate orthogonal to the polarized state given by the second polarizationmember 105. In this manner, the light beams reflected by the mirror 103can be transmitted through the first polarization member 101.

The mirror 103 is not particularly limited, and various kinds ofpublicly known mirrors can be used as appropriate. It is preferred touse a mirror having a higher reflectivity. As such a mirror, a metal(for example, aluminum) deposition mirror and a dielectric multi-layermirror has been publicly known. As the mirror 103 according to thepresent embodiment, it is preferred to use a metal deposition mirror.The reason is described by way of the ocular optical system 10L in FIG.4.

It is understood that light beams that have been emitted from the leftof the screen to reach the eye of the observer have a larger incidentangle to the mirror measured from the normal to the mirror than lightbeams that have been emitted from the right of the screen to reach theeye of the observer. A dielectric multi-layer mirror is formed bydepositing multiple optical thin films on a base to implement reflectioncharacteristics in a visible light wavelength bandwidth, but it is knownthat spectroscopic characteristics change depending on the incidentangle. Thus, if a dielectric multi-layer mirror is used as the mirror103 in the optical configuration of the ocular optical system accordingto the present embodiment, the light beams that have been emitted fromthe left of the screen to reach the eye of the observer become morebluish than the light beams that have been emitted from the right of thescreen to reach the eye of the observer. Such a state is color shadingof images, and is not preferable because authentic color reproduction isrequired in medical fields (for example, surgery).

It is preferred that the size of the mirror 103 be set depending on thesize of the image display device 107. It is preferred that theinstallation angle of the mirror 103 (for example, an angle between thereflection surface of the mirror 103 and the optical axis of the firstpolarization member 101) be set such that light of all images displayedon a display screen of the image display device 107 can be guided to theobserver.

On the display screen of the image display device 107, various kinds ofimages are displayed and presented to an observer. The image displaydevice 107 according to the present embodiment is not particularlylimited, and, for example, various kinds of publicly known displays suchas a liquid crystal display and an organic electro-luminescence (EL)display can be used.

It is preferred that the size of the image display device 107 be assmall as possible in a range where the interpupillary adjustment is notrequired and the eye box can be enlarged.

As schematically illustrated in FIG. 3A and FIG. 3B, it is preferredthat the ocular optical system 10 according to the present embodimentfurther include an ocular lens 111 on an optical path between the firstpolarization member 101 and the mirror 103. By providing the ocular lens111, an image displayed on the display screen of the image displaydevice 107 can be enlarged and provided to the observer. Thus, the imagedisplay device 107 can be further downsized by providing the ocular lens111.

Such an ocular lens 111 may be a single lens or may be a lens groupincluding a plurality of lenses. The lens surface of the ocular lens 111may be a spherical surface or an aspherical surface. Furthermore, glassmaterial of the ocular lens 111 is not particularly limited, and anypublicly known glass material can be used as appropriate.

In the ocular optical system 10 according to the present embodiment, itis preferred that a lens surface of the ocular lens 111 on the mirror103 side (when the ocular lens 111 is formed of a lens group, at least alens surface of a lens located closest to the mirror 103 on the mirror103 side) have a convex curvature as exemplified in FIG. 4.

When the optical path is folded as in the ocular optical system 10according to the present embodiment, the following ghost may begenerated other than the direct image ghost g described above.Specifically, light beams that have emitted from the image displaydevice 107 and been transmitted through the second polarization member105 may reach the surface of the ocular lens 111, light beams that havebeen reflected by the surface of the ocular lens 111 may reach themirror 103, and light beams that have reached the mirror 103 may betransmitted through the ocular lens 111 and the first polarizationmember 101 to reach the observer. Such light beams are hereinafterreferred to as “lens reflected image ghost g′”.

As exemplified in FIG. 4, at least the curvature of a lens surfacelocated closest to the mirror 103 has a convex curvature, and hence onlytangent components of the convex surface of the ocular lens 111 amongghost light fluxes are reflected to reach the mirror 103 and areprevented from reaching the observer. In other words, the convex surfaceof the ocular lens 111 serves as a diffusion mirror to diffuse ghostlight beams, and the luminance of ghost light flux per unit on anobservation eye can be suppressed. When light beam tracking simulationwas actually performed, as schematically illustrated in FIG. 5, it wasrevealed that the light flux of the lens reflected image ghost g′ isthin and the brightness is low (in other words, the F-number of the lensreflected image ghost g′ is large). In this manner, by providing theocular lens 111 between the first polarization member 101 and the mirror103, the direct image ghost and the lens reflected image ghost can besuppressed to achieve a more excellent quality image.

On the reflection surface of the mirror 103, a shield for blockingreflection light (lens reflected image ghost) reflected by the mirror103 may be provided near a position at which reflection light reflectedby a lens surface of the ocular lens 111 on the mirror 103 side amonglight beams emitted from the image display device 107 reaches thereflection surface of the mirror 103. Instead of the shield, a memberfor absorbing a lens reflected image ghost may be provided so that thelens reflected image ghost is not reflected by the reflection surface ofthe mirror 103. By providing such a mechanism, the image quality can befurther improved.

As exemplified in FIG. 6, it is conceivable to dispose the ocular lens111 on the observer side of the first polarization member 101. Also inthis case, an effect that effective light beams are reliably transmittedwhile suppressing the direct image ghost can be achieved. However, whenthe first polarization member 101 is located on the mirror 103 side ofthe ocular lens 111, the surface of the first polarization member 101may serve as a plane mirror, and, for example, as schematicallyillustrated in FIG. 7, all ghost light fluxes are reflected by thesurface of the first polarization member 101 to reach the observer.Thus, the luminance of the ghost light fluxes cannot be suppressed.

When the magnification of the above-mentioned ocular lens 111 is B, itis preferred that a relation of 3<R<5 be established. When themagnification β of the ocular lens 111 is 3 or less, the focal length ofthe ocular lens 111 can be increased to enlarge the eye box, but thesize of the image display device 107 increases. In this case, whenbinocular optical systems as illustrated in FIG. 1B and FIG. 3B are set,it may be difficult to avoid interference (physical close) between twoimage display devices 107. On the other hand, when the magnification βof the ocular lens 111 is 5 or more, the image display device 107 can beeasily downsized, but the focal length of the ocular lens 111 decreasesand the eye box is narrow, which cannot respond to eye swinging. Themagnification β of the ocular lens 111 is more preferably more than 3.5and less than 4.5 and still more preferably more than 3.7 and less than4.3.

When the angular magnification of the above-mentioned ocular lens 111 isγ, it is preferred that a relation of 1.2<γ<1.5 be established. When theangular magnification γ of the ocular lens 111 is 1.2 or less, the focallength of the ocular lens 111 can be increased to enlarge the eye box,but the size of the image display device 107 may increase, which is notpreferable. On the other hand, when the angular magnification γ of theocular lens 111 is 1.5 or more, the image display device 107 can beeasily downsized, but the focal length of the ocular lens 111 decreasesand the eye box is narrow, which cannot respond to eye swinging andwhich is not preferable. The angular magnification γ of the ocular lens111 is more preferably more than 1.2 and less than 1.4 and still morepreferably more than 1.2 and less than 1.3.

The ocular optical system 10 according to the present embodiment hasbeen described above in detail with reference to FIG. 1A to FIG. 7.

<Medical Viewer, Medical Viewer System, and Surgical System>

Next, a medical viewer 200 and a medical viewer system 600 including theocular optical system 10 according to the present embodiment and asurgical system 1000 including the medical viewer 200 are brieflydescribed with reference to FIG. 8. FIG. 8 is an explanatory diagram fordescribing the medical viewer, the medical viewer system, and thesurgical system including the ocular optical system according to thepresent embodiment.

As schematically illustrated in FIG. 8, a surgical system 1000 accordingto the present embodiment includes a surgical unit 300 and a medicalviewer system 600. For example, as schematically illustrated in FIG. 8,the medical viewer system 600 according to the present embodimentincludes a medical viewer 200, an image processing unit 400, and animage transmission unit 500. FIG. 8 illustrates the case where themedical viewer system 600 according to the present embodiment includesthe image transmission unit 500, but the medical viewer system 600 isnot necessarily required to include the image transmission unit 500.

Furthermore, it is preferred that the surgical system 1000 according tothe present embodiment include an operation unit 700 for operating thesurgical unit 300 in addition to the surgical unit 300 and the medicalviewer system 600 described above.

The medical viewer 200 according to the present embodiment is one of thedevices constituting the medical viewer system 600, and displays variouskinds of images taken by a imaging unit 301 in the surgical unit 300described later to provide various kinds of images taken by the imagingunit 301 to the user such as a doctor. In the medical viewer 200, theocular optical system 10 as described above is mounted near an ocularunit (region surrounded by broken line in FIG. 8), into which the usersuch as a doctor looks.

As described above, the ocular optical system 10 according to thepresent embodiment can provide a higher-quality image with the downsizedoptical system that does not need diopter adjustment and interpupillaryadjustment. Consequently, the user such as a doctor can observe ahigh-quality taken image (surgical site taken image) related to asurgical site (site subjected to surgery) by simply looking into theocular unit without performing diopter adjustment and interpupillaryadjustment.

The medical viewer 200 according to the present embodiment having thefunctions described above is constituted by various kinds of hardware,such as a central processing unit (CPU), a read only memory (ROM), arandom access memory (RAM), an input device, an output device, and acommunication device.

As described above, in the surgical system 1000 according to the presentembodiment, it is preferred that the operation unit 700 used for a usersuch as a doctor to operate the surgical unit 300 be provided as a unitdifferent from the surgical unit 300 and the medical viewer system 600.The operation unit 700 is provided with an operation arm 701 to beoperated by a user such as a doctor with his/her hand and an operationpedal 703 to be operated by the user such as a doctor with his/her foot.The operation unit 700 may be provided with, in addition to theabove-mentioned configuration, various kinds of buttons (not shown) foroperating the surgical unit 300. By operating the operation arm 701 andthe operation pedal 703, the user such as a doctor can control theimaging unit 301 and a surgical tool unit 303 provided in the surgicalunit 300 to a desired state.

Specifically, the user such as a doctor can operate the operation arm701 and/or the operation pedal 703 while observing an image providedfrom the ocular optical system 10 in the medical viewer 200, to controlthe imaging position or imaging magnification of the imaging unit 301and operate various kinds of surgical tools provided to the surgicaltool unit 303, such as a high-frequency knife, forceps, and a snarewire.

The user such as a doctor operates the operation unit 700 whileobserving a surgical site taken image of a surgical site, and hence itis preferred that the operation unit 700 be provided near the medicalviewer 200, and the medical viewer 200 and the operation unit 700 may beintegrated.

The surgical unit 300 is connected to each of the medical viewer system600 and the operation unit 700 in a wired or wireless manner. In thesurgical unit 300, the imaging unit 301 and the surgical tool unit 303operate based on user operation information on operation of the usersuch as a doctor transmitted from the operation unit 700. In thismanner, even when the user such as a doctor is located at a positionaway from a patient having surgery, surgical operation can be performedon the patient.

The imaging unit 301 may be, for example, various kinds of imagingcameras provided near a shadowless lamp, or may be various kinds ofcamera units provided to an endoscope unit or a microscope unit. Imagestaken by the imaging unit 301 as needed are transmitted to the imageprocessing unit 400 included in the medical viewer system 600.

The surgical tool unit 303 is a unit in which surgical tools used forvarious kinds of surgery, such as a high-frequency knife, forceps, and asnare wire, are held by various kinds of robot arms (not shown). Thesurgical tool unit 303 operates in response to user operation performedon the operation arm 701 and/or the operation pedal 703 in the operationunit 700.

The image processing unit 400 is, for example, an example of a processorunit implemented by a CPU, a ROM, a RAM, an input device, an outputdevice, and a communication device. The image processing unit 400 isconnected to each of the medical viewer 200 and the surgical unit 300 ina wired or wireless manner. The image processing unit 400 performspredetermined image processing on images obtained by taking a surgicalsite by the imaging unit 301 in the surgical unit 300 as needed, toobtain surgical site taken images. The image processing performed by theimage processing unit 400 is not particularly limited, and various kindsof publicly known image processing such as demosaicing are performed.When the image processing unit 400 generates a surgical site takenimage, the image processing unit 400 outputs the generated surgical sitetaken image to the image transmission unit 500.

The image processing unit 400 can combine a 2D/3D image supplied fromthe imaging unit 301 (for example, a camera unit provided to anendoscope unit or a microscope unit) and a processed image (auxiliaryimage) such as a user interface (UI) so that a combined imagesuperimposed with various kinds of information is generated as asurgical site taken image. It is preferred that the image processingunit 400 have various kinds of terminals, such as a DVI terminal, foroutputting the above-mentioned surgical site taken image to an externaloutput device such as an external monitor provided outside. Furthermore,the image processing unit 400 can transmit voice information to theimage transmission unit 500.

The image transmission unit 500 is, for example, an example of a relayunit implemented by a CPU, a ROM, a RAM, an input device, an outputdevice, and a communication device, and functions as a relay box foroutputting a surgical site taken image output from the image processingunit 400 to the medical viewer 200. Thus, when the relay of transmissionand reception of information between the image processing unit 400 andthe medical viewer 200 is unnecessary, the image transmission unit 500is not necessarily required to be provided in the medical viewer system600 according to the present embodiment.

The image transmission unit 500 is connected to each of the medicalviewer 200 and the image processing unit 400 in a wired or wirelessmanner. The image transmission unit 500 transmits a surgical site takenimage output from the image processing unit 400 to a medical user. Inthis manner, the surgical site taken image is presented to an observersuch as a doctor using the medical viewer 200.

It is preferred that the image transmission unit 500 have various kindsof terminals such as a DVI terminal for outputting a surgical site takenimage supplied from the image processing unit 400 to an external outputdevice such as an external monitor provided outside. The imagetransmission unit 500 can transfer images input from various kinds ofterminals such as a DVI terminal to the medical viewer 200. Furthermore,the image transmission unit 500 has terminals for connection to variouskinds of training devices, and may have a function for outputtingtraining images input from the training devices to the medical viewer200 and an external output device such as an external monitor.

FIG. 8 illustrates that the image processing unit 400 and the imagetransmission unit 500 are separate devices, but each of the imageprocessing unit 400 and the image transmission unit 500 may beimplemented as a function of a single control device.

The medical viewer 200, the medical viewer system 600, and the surgicalsystem 1000 according to the present embodiment have been brieflydescribed above.

EXAMPLES

The ocular optical system according to the present disclosure is morespecifically described below by way of examples. The following examplesare merely examples of the ocular optical system according to thepresent disclosure, and the ocular optical system according to thepresent disclosure is not limited to the following examples.

First Example

In a first example described below, the same right and left ocularoptical systems each having an ocular lens formed of two lensesillustrated in FIG. 4 were designed, and image forming simulation wasperformed.

The simulation assumed that a first polarization member 101 and a secondpolarization member 105 were present while being bonded to protectiveglass. As an image display device 107, a liquid crystal display panel(5.2 inch, half-diagonal: 66.1 mm) was used. The liquid crystal displaypanel is a liquid crystal display panel having a resolution of full HD(1920×1080 pixels). Furthermore, an angle between a reflection surfaceof a mirror 103 and an optical axis of the ocular lens was 37 degrees.

Eye relief was at a position of 20 mm from a lens surface, and thedistance (virtual image distance) from an eye to a virtual image of theliquid crystal display panel (LCD panel) was 550 mm. The right and leftLCD panels were offset by 4.923 mm in the horizontal direction to setthe binocular convergence distance to 870 mm. A reference interpupillarydistance was 62 mm, and eye relief was set so as to respond to eyeswinging of ±10.72 mm in the horizontal direction. FIG. 9 schematicallyillustrates a light beam diagram during the maximum eye swinging.

Other setting conditions are collectively indicated in Table 1 below.Lens parameters in the ocular optical system in the first example are asindicated in Table 2.

TABLE 1 First example Image display Panel (inch) 5.2 unit Panel V/2 (mm)32.4 Panel H/2 (mm) 57.6 Pixel pitch (mm) 0.060 Nyquist frequency 8(lp/mm) Ocular lens Magnification β 3.98 Angular 1.25 magnification γFocal length (mm) 172.12 Horizontal angle of view 2ω (deg) 47.0 Opticaldistortion diagonal (%) −4.19 Virtual image distance (mm) 550 Paneloffset (mm) 4.923 Convergence distance (mm) 870

TABLE 2 d-line d-line Surface Surface Curvature Surface refractive AbbeAperture number name of radius interval index number radius Object ∞−550.0000 Stop Eye relief ∞ 20.0000 2.0000 surface 2 Protective ∞ 1.10001.47140 65.53 22.3088 glass 3 First ∞ 0.2200 1.52512 56.28 22.6550polarization member 4 ∞ 3.2000 22.7216 5 First −129.5000 10.0000 1.7725049.62 23.2644 ocular lens 6 −46.7600 0.5000 24.9732 7 Second −47.49002.0000 1.84666 23.78 25.0615 ocular lens 8 −67.3400 39.8130 26.4065 9Mirror ∞ 0.0000 79.6115 10 ∞ −94.4130 40.3548 11 ∞ 0.0000 66.5581 12Second ∞ −0.2200 1.52512 56.28 66.5581 polarization member 13 Protective∞ −0.8500 1.51680 64.17 66.6177 glass 14 ∞ −0.1000 66.8492 Image Image ∞0.0000 66.8927 display unit

FIG. 10 illustrates white light through-focus MTF at the Nyquistfrequency. The MTF means image forming performance of the ocular opticalsystem when reverse light beams are tracked from the eye to the imagedisplay device (that is, when regarded as an image forming opticalsystem). In FIG. 10, the horizontal axis is an anteroposteriorthrough-focus position (mm) with reference to an image plane (imagedisplay device surface) being 0. The vertical axis is MTF (contrastvalue). When the MTF is 10% (0.1) or more, it means that an image can bevisually resolved.

In the first to fourth examples, the inch sizes of LCDs used as imagedisplay devices are different, and hence the pixel pitches are alsodifferent. In the first example, the Nyquist frequency calculated fromthe pixel pitch is 8 (lp/mm) as indicated in Table 1. Thus, in FIG. 10,the Nyquist frequency is 8 (lp/mm). Comparing Table 1 with Tables 3, 5,and 7 described below, it is understood that the Nyquist frequencybecomes larger as the inch size becomes smaller. In other words, it isnecessary to design a lens at a higher frequency, and the designdifficulty increases.

FIG. 10 illustrates MTF in the vertical direction (Y-axis direction) andMTF in the horizontal direction (X-axis direction) at screen positionsof F1: screen center, F2: screen lower left 70%, F3: screen upper left70%, F4: screen lower right 70%, and F5: screen upper right 70%.Diffraction limit (Diff.lim) represents diffraction limit. It isunderstood from FIG. 10, the ocular optical system in the first exampleenables full-HD observation because an image is resolved up to theNyquist frequency over the range of diagonal 70% from the center of ascreen to the periphery of the screen. In this manner, it is understoodthat the ocular optical system in the first example exhibits excellentcontrast and can provide a high-quality image to an observer.

Second Example

In a second example below, the same right and left ocular opticalsystems each having an ocular lens formed of two lenses illustrated inFIG. 4 were designed, and image forming simulation was performed.

The simulation assumed that a first polarization member 101 and a secondpolarization member 105 were present while being bonded to protectiveglass. As an image display device 107, a liquid crystal display panel(4.5 inch, half-diagonal: 57.0 mm) was used. The liquid crystal displaypanel is a liquid crystal display panel having a resolution of full-HD(1920×1080 pixels). Furthermore, an angle between a reflection surfaceof a mirror 103 and an optical axis of the ocular lens was 37 degrees.

Eye relief was at a position of 20 mm from a lens surface, and thedistance (virtual image distance) from an eye to a virtual image of theliquid crystal display panel (LCD panel) was 550 mm. The right and leftLCD panels were offset by 4.474 mm in the horizontal direction to setthe binocular convergence distance to 870 mm. A reference interpupillarydistance was 62 mm, and eye relief was set so as to respond to eyeswinging of ±10.72 mm in the horizontal direction.

Other setting conditions are collectively indicated in Table 3 below.Lens parameters in the ocular optical system in the second example areas indicated in Table 4.

TABLE 3 Second example Image display Panel (inch) 4.5 unit Panel V/2(mm) 28.0 Panel H/2 (mm) 49.7 Pixel pitch (mm) 0.052 Nyquist frequency10 (lp/mm) Ocular lens Magnification β 4.38 Angular 1.27 magnification γFocal length (mm) 152.32 Horizontal angle of view 2ω (deg) 44.9 Opticaldistortion diagonal (%) −4.21 Virtual image distance (mm) 550 Paneloffset (mm) 4.474 Convergence distance (mm) 870

TABLE 4 d-line d-line Surface Surface Curvature Surface refractive AbbeAperture number name of radius interval index number radius Object ∞−550.0000 Stop Eye relief ∞ 20.0000 2.0000 surface 2 Protective ∞ 1.10001.47140 65.53 18.9419 glass 3 First ∞ 0.2200 1.52512 56.28 19.1743polarization member 4 ∞ 3.2000 19.2191 5 First −168.3100 10.0000 1.7725049.62 19.8697 ocular lens 6 −44.8600 0.5000 21.2176 7 Second −47.30002.0000 1.84666 23.78 21.2228 ocular lens 8 −73.9500 39.8177 22.0615 9Mirror ∞ −73.1964 45.1404 10 ∞ −5.5500 42.2285 11 ∞ −2.0000 39.9432 12Second ∞ −0.2200 1.52512 56.28 40.5945 polarization member 13 Protective∞ −0.8500 1.51680 64.17 40.6452 glass 14 ∞ −0.1000 40.8420 Image Image ∞0.0000 40.8785 display unit

FIG. 11 illustrates MTF in the ocular optical system obtained by thesimulation. The notation system of MTF illustrated in FIG. 11 is thesame as in the first example. It is understood from FIG. 11 that theocular optical system in the second example enables full-HD observationbecause an image is resolved up to the Nyquist frequency over the rangeof diagonal 70% from the center of a screen to the periphery of thescreen. In this manner, it is understood that the ocular optical systemin the second example exhibits excellent contrast and can provide ahigh-quality image to an observer.

Third Example

In a third example below, the same right and left ocular optical systemseach having an ocular lens formed of two lenses illustrated in FIG. 4were designed, and image forming simulation was performed.

The simulation assumed that a first polarization member 101 and a secondpolarization member 105 were present while being bonded to protectiveglass. As an image display device 107, a liquid crystal display panel(4.0 inch, half-diagonal: 50.7 mm) was used. The liquid crystal displaypanel is a liquid crystal display panel having a resolution of full-HD(1920×1080 pixels). Furthermore, an angle between a reflection surfaceof a mirror 103 and an optical axis of the ocular lens was 37 degrees.

Eye relief was at a position of 20 mm from a lens surface, and thedistance (virtual image distance) from an eye to a virtual image of theliquid crystal display panel (LCD panel) was 550 mm. The right and leftLCD panels were offset by 3.986 mm in the horizontal direction to setthe binocular convergence distance to 870 mm. A reference interpupillarydistance was 62 mm, and eye relief was set so as to respond to eyeswinging of ±10.72 mm in the horizontal direction.

Other setting conditions are collectively indicated in Table 5 below.Lens parameters in the ocular optical system in the third example are asindicated in Table 6.

TABLE 5 Third example Image display Panel (inch) 4.0 unit Panel V/2 (mm)24.9 Panel H/2 (mm) 44.2 Pixel pitch (mm) 0.046 Nyquist frequency 11(lp/mm) Ocular lens Magnification β 4.92 Angular 1.31 magnification γFocal length (mm) 131.57 Horizontal angle of view 2ω (deg) 45.1 Opticaldistortion diagonal (%) −4.77 Virtual image distance (mm) 550 Paneloffset (mm) 3.986 Convergence distance (mm) 870

TABLE 6 d-line d-line Surface Surface Curvature Surface refractive AbbeAperture number name of radius interval index number radius Object ∞−550.0000 Stop Eye relief ∞ 20.0000 2.0000 surface 2 Protective ∞ 1.10001.47140 65.53 19.0151 glass 3 First ∞ 0.2200 1.52512 56.28 19.2498polarization member 4 ∞ 3.2000 19.2950 5 First −213.4000 11.0000 1.7725049.62 20.0287 ocular lens 6 −42.3600 0.5000 21.3875 7 Second −43.60002.5000 1.84666 23.78 21.3537 ocular lens 8 −70.4000 39.8177 22.3602 9Mirror ∞ −60.1319 42.8282 10 ∞ 0.0000 37.7561 11 ∞ −6.8600 34.5716 12Second ∞ −0.2200 1.52512 56.28 36.1744 polarization member 13 Protective∞ −0.8500 1.51680 64.17 36.2249 glass 14 ∞ −0.1000 36.4210 Image Image ∞0.0000 36.4574 display unit

FIG. 12 illustrates MTF in the ocular optical system obtained by thesimulation. The notation system of MTF illustrated in FIG. 12 is thesame as in the first example. It is understood from FIG. 12 that theocular optical system in the third example enables full-HD observationbecause an image is resolved up to the Nyquist frequency over the rangeof diagonal 70% from the center of a screen to the periphery of thescreen. In this manner, it is understood that the ocular optical systemin the third example exhibits excellent contrast and can provide ahigh-quality image to an observer.

Fourth Example

In a fourth example below, the same right and left ocular opticalsystems each having an ocular lens formed of three lenses illustrated inFIG. 13 were designed, and image forming simulation was performed.

The simulation assumed that a first polarization member 101 and a secondpolarization member 105 were present while being bonded to protectiveglass. As an image display device 107, a liquid crystal display panel(4.0 inch, half-diagonal: 50.7 mm) was used. The liquid crystal displaypanel is a liquid crystal display panel having a resolution of full-HD(1920×1080 pixels). Furthermore, an angle between a reflection surfaceof a mirror 103 and an optical axis of the ocular lens was 37 degrees.

Eye relief was at a position of 20 mm from a lens surface, and thedistance (virtual image distance) from an eye to a virtual image of theliquid crystal display panel (LCD panel) was 550 mm. The right and leftLCD panels were offset by 3.959 mm in the horizontal direction to setthe binocular convergence distance to 870 mm. A reference interpupillarydistance was 62 mm, and eye relief was set so as to respond to eyeswinging of ±10.72 mm in the horizontal direction.

Other setting conditions are collectively indicated in Table 7 below.Lens parameters in the ocular optical system in the fourth example areas indicated in Table 8.

TABLE 7 Fourth example Image display Panel (inch) 4.0 unit Panel V/2(mm) 24.9 Panel H/2 (mm) 44.2 Pixel pitch (mm) 0.046 Nyquist frequency11 (lp/mm) Ocular lens Magnification β 4.95 Angular 1.43 magnification γFocal length (mm) 127.60 Horizontal angle of view 2ω (deg) 45.7 Opticaldistortion diagonal (%) −5.65 Virtual image distance (mm) 550 Paneloffset (mm) 3.959 Convergence distance (mm) 870

TABLE 8 d-line d-line Surface Surface Curvature Surface refractive AbbeAperture number name of radius interval index number radius Object ∞−550.0000 Stop Eye relief ∞ 20.0000 2.0000 surface 2 Protective ∞ 1.10001.47140 65.53 22.1154 glass 3 First ∞ 0.2200 1.52512 56.28 22.4551polarization member 4 ∞ 3.2000 22.5205 5 First −195.3200 8.4200 1.7725049.62 23.3927 ocular lens 6 −60.1100 3.5800 24.7990 7 Second −39.39003.0000 1.71736 29.50 24.8258 ocular lens 8 Third −191.3500 10.00001.77250 49.62 29.0675 ocular lens 9 −48.0000 43.0000 29.8517 10 Mirror ∞−59.5662 67.7357 11 ∞ −3.2840 52.8697 12 ∞ −2.0000 50.2635 13 Second ∞−0.2200 1.52512 56.28 51.0092 polarization member 14 Protective ∞−0.8500 1.51680 64.17 51.0609 glass 15 ∞ −0.1000 51.2627 Image Image ∞0.0000 51.3037 display unit

FIG. 14 illustrates MTF in the ocular optical system obtained by thesimulation. The notation system of MTF illustrated in FIG. 14 is thesame as in the first example. It is understood from FIG. 14 that theocular optical system in the fourth example enables full-HD observationbecause an image is resolved up to the Nyquist frequency over the rangeof diagonal 70% from the center of a screen to the periphery of thescreen. In this manner, it is understood that the ocular optical systemin the fourth example exhibits excellent contrast and can provide ahigh-quality image to an observer.

While exemplary embodiments of the present disclosure have beendescribed above in detail with reference to the accompanying drawings,the technical scope of the present disclosure is not limited to theexamples. It is obvious that a person with ordinary skills in thetechnical field of the present disclosure could conceive of variouskinds of changes and modifications within the range of the technicalconcept described in the claims. It should be understood that thechanges and the modifications belong to the technical scope of thepresent disclosure.

The effects described herein are merely demonstrative or illustrativeand are not limited. In other words, the features according to thepresent disclosure could exhibit other effects obvious to a personskilled in the art from the descriptions herein together with or inplace of the above-mentioned effects.

The following configurations also belong to the technical scope of thepresent disclosure.

(1)

An ocular optical system, including, on an optical path viewed from anobserver side, at least:

a first polarization member;

a mirror;

a second polarization member; and

an image display device in this order, wherein

a polarized state in the first polarization member and a polarized statein the second polarization member are orthogonal to each other.

(2)

The ocular optical system according to (1), further including an ocularlens disposed on an optical path between the first polarization memberand the mirror, wherein

a lens surface of the ocular lens on the mirror side has a convexcurvature.

(3)

The ocular optical system according to (2), wherein a relation of 3<β<5is satisfied, where B is a magnification of the ocular lens.

(4)

The ocular optical system according to (2) or (3), wherein a relation of1.2<γ<1.5 is satisfied, where γ is an angular magnification of theocular lens.

(5)

The ocular optical system according to any one of (2) to (4), wherein,on a reflection surface of the mirror, a shield for blocking reflectionlight reflected by the mirror is provided near a position at whichreflection light reflected by a lens surface of the ocular lens on themirror side among light beams emitted from the image display devicereaches the reflection surface of the mirror.

(6)

The ocular optical system according to any one of (1) to (5), whereinthe first polarization member and the second polarization member arelinear polarizing plates.

(7)

The ocular optical system according to any one of (1) to (5), wherein

the first polarization member is a linear polarizing plate, and

the second polarization member is a circular polarizing plate formed ofa ¼ wavelength plate.

(8)

The ocular optical system according to any one of (1) to (5), wherein

the first polarization member is a linear polarizing plate, and

the second polarization member is a ½ wavelength plate.

(9)

The ocular optical system according to any one of (1) to (5), wherein

the first polarization member is a linear polarizing plate, and

the second polarization member is a polarization member in which alinear polarizing plate and a ½ wavelength plate are disposed in thisorder from the observer side.

(10)

A medical viewer, including an ocular optical system including, on anoptical path viewed from an observer side, at least:

a first polarization member;

a mirror;

a second polarization member; and

an image display device in this order, wherein

a polarized state in the first polarization member and a polarized statein the second polarization member are orthogonal to each other.

(11)

A medical viewer system, including:

an image processing unit for performing image processing on an image inwhich a surgical site that is a site subjected to surgery is taken, andoutputting an obtained surgical site taken image; and

a medical viewer for presenting the surgical site taken image outputfrom the image processing unit to an observer, wherein

the medical viewer includes an ocular optical system including, on anoptical path viewed from an observer side, at least:

-   -   a first polarization member;    -   a mirror;    -   a second polarization member; and    -   an image display device in this order, and

a polarized state in the first polarization member and a polarized statein the second polarization member are orthogonal to each other.

(12)

The medical viewer system according to (11), further including an imagetransmission unit for transmitting the surgical site taken image outputfrom the image processing unit to the medical viewer.

REFERENCE SIGNS LIST

-   -   10 ocular optical system    -   101 first polarization member    -   103 mirror    -   105 second polarization member    -   107 image display device    -   111 ocular lens    -   200 medical viewer    -   300 surgical unit    -   301 imaging unit    -   303 surgical tool unit    -   400 image processing unit    -   500 image transmission unit    -   600 medical viewer system    -   700 operation unit    -   701 operation arm    -   703 operation pedal    -   1000 surgical system

1. An ocular optical system, comprising, on an optical path viewed froman observer side, at least: a first polarization member; a mirror; asecond polarization member; and an image display device in this order,wherein a polarized state in the first polarization member and apolarized state in the second polarization member are orthogonal to eachother.
 2. The ocular optical system according to claim 1, furthercomprising an ocular lens disposed on an optical path between the firstpolarization member and the mirror, wherein a lens surface of the ocularlens on the mirror side has a convex curvature.
 3. The ocular opticalsystem according to claim 2, wherein a relation of 3<β<5 is satisfied,where β is a magnification of the ocular lens.
 4. The ocular opticalsystem according to claim 2, wherein a relation of 1.2<γ<1.5 issatisfied, where γ is an angular magnification of the ocular lens. 5.The ocular optical system according to claim 2, wherein, on a reflectionsurface of the mirror, a shield for blocking reflection light reflectedby the mirror is provided near a position at which reflection lightreflected by a lens surface of the ocular lens on the mirror side amonglight beams emitted from the image display device reaches the reflectionsurface of the mirror.
 6. The ocular optical system according to claim1, wherein the first polarization member and the second polarizationmember are linear polarizing plates.
 7. The ocular optical systemaccording to claim 1, wherein the first polarization member, and thesecond polarization member are circular polarizing plates respectivelyformed of a linear polarizing plate and a ¼ wavelength plate.
 8. Theocular optical system according to claim 1, wherein the firstpolarization member is a linear polarizing plate, and the secondpolarization member is a ½ wavelength plate.
 9. The ocular opticalsystem according to claim 1, wherein the first polarization member is alinear polarizing plate, and the second polarization member is apolarization member in which a linear polarizing plate and a ½wavelength plate are disposed in this order from the observer side. 10.A medical viewer, comprising an ocular optical system including, on anoptical path viewed from an observer side, at least: a firstpolarization member; a mirror; a second polarization member; and animage display device in this order, wherein a polarized state in thefirst polarization member and a polarized state in the secondpolarization member are orthogonal to each other.
 11. A medical viewersystem, comprising: an image processing unit for performing imageprocessing on an image in which a surgical site that is a site subjectedto surgery is taken, and outputting an obtained surgical site takenimage; and a medical viewer for presenting the surgical site taken imageoutput from the image processing unit to an observer, wherein themedical viewer includes an ocular optical system including, on anoptical path viewed from an observer side, at least: a firstpolarization member; a mirror; a second polarization member; and animage display device in this order, and a polarized state in the firstpolarization member and a polarized state in the second polarizationmember are orthogonal to each other.
 12. The medical viewer systemaccording to claim 11, further comprising an image transmission unit fortransmitting the surgical site taken image output from the imageprocessing unit to the medical viewer.